The present invention relates to an invertible pump sprayer for dispensing a liquid material in the form of a spray in any direction. By a "spray" it is meant that the liquid is broken-up into individual particles.
It is desirable to apply many cosmetics and pharmaceuticals such as hair setting solutions, deodorants, antiseptics and anesthetics in the form of a spray, preferably in the form of a fine spray. One popular method of forming sprays has been by producing an aerosol containing a fluorocarbon propellant. This method is capable of placing a mist into the air having an average particle size range of about 50-500 microns from a pressurized container.
One of the disadvantages of forming such aerosols is the necessity of using a dispensing valve having an extremely fine-bore. Where the liquid material to be dispensed has a tendency to form a film, or where the liquid material is a solution of a solid substance, it has been a common experience that the valve becomes clogged and, generally, cannot readily be cleaned. As a result, the aerosol dispenser becomes useless and must be discarded before the contents have been completely used.
Another disadvantage stems from the recently aroused suspicion that the common, non-inflammable fluorocarbon propellants might be destroying the ozone layer of the upper atmosphere. Accordingly, other methods of applying deodorants and the like in the form of a spray have been tried. Two such methods are:
(1) The use of a manually-operated pump spray device, and
(2) the use of a pressurized dual chamber container that separates the material to be dispensed from a propellant.
However, both of these methods have several disadvantages.
While pump sprays can provide a relatively fine spray, on the order of average particle sizes of about 100-500 microns, provided the viscosity of the product is no higher than approximately 40-45 cps. at room temperature, at viscosities higher than this they provide a very coarse spray or dispense the product in the form of a stream rather than a spray. Furthermore, many products even with viscosities below 40 cps., which form a spray at room temperature, form a stream at temperatures below room temperature.
A second disadvantage in the use of a pump spray device results from the fact that the device must be held in an almost upright position in order to function. When inverted or when held in a horizontal position after half or more of the contents has been emptied, the end of the dip tube or inductor is no longer in contact with the liquid and the liquid, therefor, cannot be pumped. This is particularly disadvantageous when applying anesthetics to various parts of the body since this usually requires that the device be held in a semi- or totally-inverted position.
A third disadvantage of the use of a pump spray device is that it is difficult to completely empty the device, particularly if, in use, the dip tube becomes bent and does not rest on the very bottom of the container portion of the device.
The aforementioned second method that has been tried to obtain a spray is by means of a dual chamber container wherein one chamber consists of an inner flexible container which contains the product to be dispensed. The top of this inner flexible container is connected to a dispensing valve. A perforated dip tube may be attached to the dispensing valve; if so, it extends to the bottom of the container. A rigid outer container encloses the flexible inner container. Propellant is provided in the space between the flexible inner container and the walls of the outer container. When the dispenser valve is opened, the pressure of the propellant vapor on the inner flexible container forces the product out of the container.
This container has certain advantages over the pump spray:
(1) It can be held in any direction, and
(2) the product is almost completely emptied from the container.
However, it has three serious disadvantages.
(1) It dispenses most products in the form of a stream instead of a spray. Even with products having a viscosity of as low as 20-25 cps., only a coarse spray having an average particle size of about 1000 microns is obtained, and at viscosities of 35 cps. or higher, only a stream is obtained.
(2) Since a relatively high pressure is needed to obtain even a coarse spray, a very low boiling propellant is required. This causes problems in disposing of the used container. If a fluorocarbon is used, there is still the danger of affecting the ozone layer of the atmosphere should the container rupture after being discarded. If a low boiling hydrocarbon is employed, such as propane or isobutane, there is danger of fire or explosion.
(3) Again, because of the need for using a propellant, the outside container must be made of a material sufficiently strong to withstand the necessary high pressure. A metal container is the only type practical for this purpose. This has obvious disadvantages over the use of a plastic container which is lighter, less expensive and ecologically preferable.
It is a general object of the present invention to overcome all of the above disadvantages of the conventional aerosol container, the pump spray and the dual chamber container. More particularly, one object of the present invention is to provide a pump sprayer which, with the same liquid, provides a means of obtaining a finer spray than a conventional spray pump or a dual chamber aerosol. Another object is to provide a pump sprayer which provides a means of obtaining a spray even with viscosities as high as approximately 100 cps. Another object is to provide a sprayer for dispensing a spray regardless of the position in which the sprayer is held. A further object is to provide a sprayer in which the contents are emptied almost completely. An additional object is to provide a sprayer that will produce a spray at temperatures below room temperature. Another object is to provide a sprayer in which a propellant is not ordinarily required and, if one is used, wherein a relatively non-flammable, relatively low pressure propellant can be employed. A still further object is to provide a pump sprayer in which the outer container can be made of plastic.
These and the other objects which will become apparent to those skilled in the art are achieved in accordance with the present invention by providing a pump sprayer comprising means for containing the material to be dispensed which collapses as the liquid material therein is dispensed and a spray pump means operatively associated with the means that contains the material to be dispensed for dispensing the material as a spray.
In accordance with the present invention, it has been surprisingly discovered that, when a spray pump is used in combination with a collapsible container, not only is it possible to obtain a spray instead of a stream, but it is also possible to obtain such a spray with materials having viscosities as high as 100 cps.
In a preferred form of the invention, the means for containing the material to be dispensed is a flexible container made of suitable plastic material that is disposed within an outer rigid protective shell or container. Such an inner flexible container can, for example, be a flexible bag that collapses inwards or a flexible multi-pleated container of the type which collapses from the bottom upward. Usually, the flexible container is made of a plastic.
The flexible container disposed within the outer protective shell or container can be exposed to atmospheric pressure by providing at least one opening in the outer shell or container that communicates with the atmosphere. For example, the outer protective shell or container may be a perforated tubular-shaped member having a cylindrical side wall, a flat bottom end wall, and a flat or curved upper end wall with an opening through which the spray pump is inserted for fluid-tight connection with the flexible container disposed within the outer protective shell or container.
In another embodiment, the flexible container can be part of a dual chamber container having an outer rigid container spaced from the inner flexible container. The space between the flexible container and the outer rigid container is sealed so that a low pressure propellant can be placed in the space to promote collapse of the flexible container when because of the stiffness of the flexible container, greater than atmospheric pressure is required to cause it to collapse.
It will be appreciated that when a propellant is used, the outer container is ordinarily made of metal; but when no propellant is employed, the outer container can be and preferably is made of rigid plastic.
The spray pump used in accordance with this invention is identical to the conventional spray pumps which are commerically available with the exception that the dip tube or inductor portion is modified to suit the specific demands of the present invention. Thus, it will be understood that the spray pump includes conventional elements such as a spray head, spring biased valve and means for attaching the spray pump in fluid tight manner to the flexible container for the liquid material to be dispensed.
Additional features and advantages of the present invention will become more apparent from the following detailed description and the accompanying drawings which show, for purposes of illustration only, different embodiments of the present invention.